Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 545,852 websites that are Cloudflare Rocket Loader Customers. We know of 32,691 live websites using Cloudflare Rocket Loader and an additional 513,161 sites that used Cloudflare Rocket Loader historically and 16,283 websites in the United States.
Get a list of 545,852 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 32,691 currently live websites and an additional 15,958 domains that redirect to sites in this list. 513,161 sites that used this technology previously and 16,283 websites in the United States currently using Cloudflare Rocket Loader.